Process of producing naphtha from hydrocarbon oils



Sept. 22, 1931. M. l.. cHAPPl-:LL

PROCESS OF PRODUCING NAPHTHA FROM HYDROCARBON OILS Filed Dec.

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Patented Sept. 22, 1931 NITED STATES PATENT OFFICE MARVIN L. CHAPPELL, OF LOS ANGELES, CALIFORNIA, ASSIGNOR TO STANDARD OIL COMPANY F CALIFORNIA, OF SAN FRANCISCO, CALIFORNIA,

DELAWARE PROCESS 0F PRODUGING NAPHTHA FROM HYDROCARBON OILS Application led December l, 1926. Serial No. 151,876.

This invention relates to a process of treating hydrocarbon oil to produce low boiling point oil such as naphtha or gasoline.

An object of the present invention is to provide a process of treating hydrocarbon oil with metallic halide which will enable the production of a larger percentage of naphtha from the hydrocarbon oil than can be produced in accordance with the usual processes.

More particularly an object of the present invention is to provide a process for treat ing hydrocarbon oil with metallic halide in which the fresh metallic halide is brought first into contact with the hydrocarbon oil or vapors thereof at a comparatively low temperature and is thereafter'contacted at an increased or higher temperature with a hydrocarbon oil. Preferably this is accomplished byfeeding the metallic halide into a reflux tower connected with a reaction chamber so that the metallic halide first comes into contact with the vapors and condensate products within said tower and therefrom passes into 5 the reaction chamber. .In this way, the first reaction between the metallic halide and hyi drocarbon oil is at a comparatively low temperature while the second reaction in the reaction chamber is at an increased tempera- $0 ture. Therefore, the fresh metallic halide has an opportunity for reacting upon hydrocarbon oil in the absence of any metallic halide sludge produced from the high tem- I perature treatment.

A further object of the present invention is to provide a method for producing naphtha from hydrocarbon oil in which the naphtha. is produced partially by a metallic halide reaction and partially by a thermal cracking reaction with such passage of materials from one reaction to the other asis conductive to the most efficient production' of the low boiling point oil or naphtha. In accordance with the present process, all of the hydrocarbon oil charged into the cracking apparatus is first subjected to an action with metallic halide with the result that said oil is both freed from sulfur content and polymerized to eliminate unsaturated materials. At the same time, the condensed high boiling point oils or hydrocarbon which has a substantially lower sulfur content than the naphthas .normally produced by a cracking reaction and all fractions of the hydrocarbon or petroleum oil are repeatedly acted upon until the entire feedof petroleum oil may be converted into either naphtha or coke.

Various further objects and advantages of the present invention will be apparent from a description of a preferred form or example of a process embodying the invention. For this purpose, reference is made to the accompanying drawing in which there is illustrated a form of apparatus in which the process of the present invention may be performed.

A CORPORATION OF The drawing represents a diagrammatic view of the apparatus in which the parts are mainly in vertical section.

Referring to the drawing, the preferred continuous process is performed by passing the fresh oil to be treated from a line 2 by means of a pump 6 through a preheater 3 to' a line 4, and hence through a heating coil 5 into a reaction chamber 7. The process will be described referring particularly to the treatment with aluminum chloride as the metallic halide, but it is to be understood, however, that aluminum chloride is to be regarded merely as an example of a metallic halide. The preheater 3, as later brought out, preferably is positioned `Within a dephlegmator or refiux tower 8 for the reaction chamber 7, thus operating as a control over the discharge temperature of vapors from said tower. The heating coil 5 is preferably of the oncethrough type and is located within any suitable heating means, such as the furnace 9 having the burner 10. The reaction chamber 7 may be of any suitable type for commingling aluminum chloride and hydrocarbon oil at a reactin temperature, being indicated as prefera ly a orizontal cylindrical tank having an agitator 11.- Said reaction chamber 7 is preferably provided with a valved residual withdrawal line 12 and is also referably mounted on-a furnace 13 prolvide with a burner orother suitable heat- Y tained in reaction chamber7. Said temperature will depend'largely upon the character l of oil supplied to the system and the percentage of aluminum chloride provided for reacting therewith and also upon'the pressure emplo ed and the extent of reaction desired in sai chamber. -Generally the temperature will range between 500 and 600 F., although temperature from 400 to 700 F. may at times be employed. Particularly with the higher temperatures, a certain amount of the hydrocarbon oil may be thermally decomposed' or cracked and vaporized from the system, in which case however said decomposed oil will be reacted upon by the aluminum chloride in dephlegmator 8. 4It is an advantage also in the process to operate at comparatively 'high temperatures, such as 600 F., or higher, when the aluminum chloride conversion -process is carried out, together with the subsequent thermal cracking operation as such h igher temperatures .operate to insure a more elicient removal of the sulfur content of the oil.

Within reaction chamber 7 and upon the vapor 'separating apparatus, therefore, a pressure is preferably employed. Pressure however, is not essential to this portion of the reaction and, in fact, below atmospheric pressure may be employed. However, it is generally found that the elliciency is `increased where the pressure upon the reaction chamber 7 is maintained above atmospheric,

for example, froml to 50 pounds gage.

Additional heat may be su plied to the reaction chamber 7, if desire inorder to maintain the reaction temperature, although this is not generally necessary. Within the reaction chamber 7, the hydrocarbon oil reacts with metallic halide or metallic halide fluid sludge or tar from dephlegmator or reflux tower 8. The reaction in chamber 7 is preferably regulated so that all of the metallic halidesludge fed thereinto is reduced to a solid mass or coke while at the same time all of the hydrocarbon oil not decomposed into coke is vaporized from the chamber, to-

it is condensed and hence passed to the naphthaor gasoline tank 18 which is indicated as preferably provided with a valved ventline 19 In the dephlegmator or reflux tower 8, the metallic halide is added either continuously or intermittently. Said metallic halide is added from charger l20 which is indicated asl provided witha hopper 21 for use when the .g

material is added in solid form land with a line 22through which liquid metallic halide may be added, for example, metallic halide admixed with -suicijent hydrocarbon oil to make the same liquid.

Th fresh metallic halide first comes vinto contact -with hydrocarbon voil in` thedephlegmator or reflux tower8 whereinl it reacts upon the hydrocarbon oil-for the further vproduction of. naphtha and also for the polymerization. ofany cracked stock which might have been formed in reactiontower'7. It is understood that the metallic halide'in its descent to the reflux tower 8 progressively comes into contact with the condensed oil' on each ofthe different compartments of thel dephlegmator and is finally collected in the lower end of the reux tower and hence assed vthrough line 23 to reaction chamber 7). Due to the cooling action of the feed oil and heat exchanger or planer 3, the temperature within the reflux tower 8.is lower than the temperature of reaction chamber 7. For example, when operating at15 pounds pressure, the discharge temperature at the topof the dephlegmator is ordinarily around 330 F., while the lower end of the dephleg matorwill operate generally about 100 F. lower-than the temperature of the oil or ad- ,mixture within reaction chamber 7.

In vthebottom of dephlegmator or rellux tower 8 both metallic halide sludge and condensed high boiling point oils are collected. These materials lstratify so that the hydrocarbon oil occupies the upper layer. rlhe reflux tower 8 is indicated as preferably provided with an automatic controlfor a valve 24 on the line 23 which conducts the metallic halide to reaction chamber 7. said control including the oat 25. The float 25 or other suitable liquid level indicating and regulating device adapted to float on the tarry reaction sludge, may be connected 'in any suitable manner with the valve 24 so as to open said valve whenever the sludge accumulates.

The oil present above the sludge layer is withdrawn from the tower 8 by line 26.

The high boiling point hydrocarbon oil condensed within the reflux tower 8 may be Withdrawn therefrom to a receiver for processing in any desired manner or may be passed again to reaction chamber 7 but preferably is passed to a thermal cracking apparatus of any desired or` suitable type. It is understood that the feature of adding the metallic halide to a reflux tower of the reaction chamber 7 is not necessarily dependent upon the simultaneous passage of the reiuxed oil to a cracking precess. Preferably, however, said condensed oil is continuously passed` from reflux tower 8 through line 26 wherein it is raised in pressure by pump 27 and passed once through a heating coil 28. Within the heating coil 28, said oil is raised'to a cracking temperature such, for example, as around 750 to 850 F., the heating coil 28 being indicated as heated by suitable means such, for example, as the furnace 29 having the burner 30.

From the heating coil 28, the hydrocarbon oil is passed to a reaction chamber 31 wherein the cracking reaction is permitted to complete itself and the produced naphtha is permitted to vaporize. In said reaction chamber 31, the oil is reduced to naphtha and a tarry resdue which may be continuously withdrawn through line 32 or the oil may be reduced to naphtha and coke.. The vapors from reaction chamber 31 are passed through vapor line 33 to a reflux tower or dephlegmator 34. Said reflux tower 34 is indicated as provided with a planer 35 having water inlet and outlet lines 36 and 37, respectively, by means of which the temperature of the .vaporsl disv charged from the tower may be regulated to condense therefrom all fractions which have boiling points without the range of the 'desired naphtha or gasoline. Saidnaphtha or gasoline passes from the reflux tower 34 through line 38 to a condenser 39 and hence into a storage vessel 40 having a valved vent line 41. The presssure imposed upon the oil during the before-described cracking reaction is generally from 8O pounds to 300 pounds per square inch although higher pressures may be employed. It is understood that the particular details of the cracking reaction described are not essential to the present process.

The condensed high boiling point oils in dephlegmator 34 are preferably passed through a line 42 into the metallic halide reaction chamber 7. In said reaction chamber 7, said high boiling point oils', a considerable portion of which have been rendered unsaturated through the cracking reaction, will be readily acted upon by the metallic halide and converted either into naphtha or saturated high boiling point oils.

By the process thus described, both metallic halide conversion and thermal conversion are applied to a hydrocarbon oil under such conditions as are found to produce or result in the maximum conversion of said oil to naphtha with the minimum loss of hydrocarbon oil, -it being found that the two processes inter-relatedv in the beforedescribed manner coordinate together most efficiently in the production of naphtha. All of the hydrocarbon oil subjected to thermal decomposition is first subjected to contact or reaction with a metallic halide thereby removing unsaturated materials and surfur bearing constituents therefrom which are detrimental in the thermal cracking reaction and all of the high boiling point oil containing unsaturated materials derived from the thermal cracking reaction is recirculated to the zone where the'hydrocarbon oil is undergoing reaction with metallic halide, whereby said hydrocarbon oil is rendered saturated and in condition for better processing'for the production of further naphtha.

While the process herein described is well adapted to carry out the objects of the present invention, it is understood that various modifications and changes may be made withp tallic halide into the system, and passing the metallic halide and. metallic halide reaction products from said reflux zone to said reaction zone.

2. A process of treating hydrocarbon oil with metallic halide which comprises contacting fresh hydrocarbon oil and metallic halide in a reaction zone under conditions to reduce all of the tarry residue containing metallic halide to a solid mass or coke and at the same .time vaporizev all of the hydrocarbon oil not decomposed into coke, passing the vapors to a reflux Zone, thereinintroducing the fresh metallic halide into the system, passing the `metallic halide and metallic halide reaction products from said reflux zone to said reaction zone. withdrawing the condensed high boiling point oils in said reflux Zone, and subjecting said condensed oils to the requisite temperature and pressure to thermally decompose said oils without a halide catalyst into lower boiling point oils.

3. A continuous process of treating hydrocarbon oil which comprises continuously supplying fresh hydrocarbon feed oil to a reac- I t1ony zone, continuously passing vapors from said reaction zone t0 a reflux zone, supplying metallic halide to said reflux zone, separating metallic halide from condensed high boiling oils from said reflux zone, passing metallic halide from such reflux zone to said reaction zone, withdrawing the condensedl high boiling point. oils from said reflux zone, and subjecting the same to the requisite temperature and pressure to thermally decompose the same Without a halide catalyst into lower boiling point oils. A

4. A process of treating petroleum oils with metallic halide comprising maintaining a body of petroleum oil and metallic halideundergoing reaction in a reaction zone, evolving vapors from said mixture, passing the vapors to a reflux zone contacting metallic halide with said vapors within said zone at a progressively increasing temperature, separately vaporizing oils condensed Within said reflux zone, passing said vapors to a second reflux zone and returning oil condensed within said second reflux zone to the first reflux zone.

5. A process of treating petroleum oils with metallic halide comprising maintaining a body of petroleum oil and metallic halide undergoing reaction in a reaction zone, evolving vapors from said mixture, passing the vapors to a reflux Zone, contacting metallic halide with said vapors Within said zone at a progressively increasing temperature, separatel-y vaporizing oils condensed Within said reflux zone, passing said vapors to a second reflux zone and returning oil condensed Within said second reflux Zone to the reaction zone. o

6. A process of the character described comprising contacting metallic halide with vapors from an oil-metallic halide reaction zone at progressively increasing temperatures in a reflux. zone, revaporizing oil condensed within said reflux Zone under cracking temperature and pressure conditions, passing such vapors through a second reflux zone and returning oil condensed within said second reflux zone to the first reflux zone.

7. In a process of treating hydrocarbon oils with metallic halide, the steps of contacting feed oil with partially spent metallic halide in a reaction zone at reaction temperatures, passing oil vapors evolved by such contact into a reflux zone, contacting said oil vapors with fresh metallic halide in such reflux zone, discharging treated oil vapors from said reflux zone, separately discharging condensed andpartially treated oil from said reflux zone, and separately vaporizing and dephlegmating said partially treated oil.

Signed at' San Francisco, California, this 19th day of November, 1926.

MARVIN L. CHAPPELL. 

